This invention relates generally to electric switches and more specifically to electric switches which are responsive separately to two different conditions.
In many mechanical and electrical apparatus sensors are utilized to monitor and respond to various conditions to ensure proper operation of the apparatus and prevent unsafe or undesirable operation thereof. For example, in refrigerator compressors it is common practice to provide a pressure responsive electric switch such as that shown and described in U.S. Pat. No. 3,584,168, assigned to the assignee of the present invention. In that patent a switch is described having a port fitting adapted to be attached to a pressure source so that when the pressure rises to a predetermined level a diaphragm snaps from a convex to a concave configuration transmitting its motion through a motion transfer pin to a movable contact arm of the switch to either open or close an electric circuit.
It is also common practice to mount a temperature responsive electric switch in heat transfer relationship with selected portions of a compressor apparatus such as the compressor shell. For example, a temperature responsive electric switch of this type is shown and described in U.S. Pat. No. 3,416,115 also assigned to the assignee of the present invention. In that patent a switch is described having a snap acting thermostatic disc thermally coupled to a thermally conductive surface which in turn is mounted in heat transfer relation with a surface whose temperature is being monitored, i.e. the compressor shell. The disc is adapted to move from a first convex or concave configuration to the opposite concave, convex configuration, upon reaching a selected temperature with its motion transferred through a motion transfer pin to a movable contact arm of the switch to either open or close an electrical circuit.